| 摘要 |
PURPOSE:To detect only the defect of a pinhole by separating only an output signal based upon the pinhole from an output signal based upon another cause. CONSTITUTION:Spot light 1 is projected on a coating film formed on a traveling sheet 9 or film. Then its transmitted or reflected light is converted photoelectrically by a photomultiplier tube, a phototransistor 2, a DC amplifier 4 connected thereto, etc. Then a high-pass filter circuit 5 cuts a low-frequency output signal of long wavelength based upon an irregularity in the coating of the coating film. Then a monostable multivibrator 7 rectifies the output of a comparator 6 as a pinhole decision device. The output of the multivibrator 7 is recorded 8 as a pinhole output. Consequently, the pinhole is easily and securely inspected. |
